1. Field of the Invention
The present invention relates generally to the field of marine surface vessels. More specifically the present invention relates to a surface operating marine vessel which is supported by a cushion of pressurized air supplied to the air cushion by blowers.
2. Description of the Prior Art
There have been many types of marine surface vessels, some of which have utilized a cushion of pressurized gas such as air to reduce friction with the surface of the water. Some such marine vessels operate in a surface effect condition by entrapping a cushion(s) of artificially pressurized air between the vessel and the surface of the water such as by utilizing a plurality of blowers which fill a flexible skirt at the bottom of the vessel. Others use a ram effect of ambient air that is sandwiched between the vessel water surface when the vessel is travelling at higher speeds. The first type of vessel are called hovercrafts or Surface Effect Ships (SES""s), and the latter are called Wing In Ground Effect (WIG), Wing In Surface Effect Craft, or more simply wingships. Other vessels use a combination of blowers and ram effect to provide a pressurized air cushion below the vessel. The common denominator to all of these vessels is that pressurized air is disposed between the vessel and the surface of the water supports the majority of the vessel weight. The operating efficiency of SES vessels is much greater than that of conventional marine vessels.
A vessel which utilizes blowers to create an air cushion in a pair of lower recesses is disclosed in Burg U.S. Pat. No. 4,890,564 issued on Jan. 2, 1990. Burg teaches a marine surface vessel that includes a center bow and side hulls that is supported, at least in part, by a cushion of pressurized air supplied by a powered blower. The pressurized gas cushion is restrained within a pair of longitudinally extending recesses built into the underside of the hull separated by a parallel center divider. The recesses are closed at respective bow ends of the hull by respective forward movable seals that increase movable seal life. The recesses are closed at respective stem ends by respective movable stem seals that allow control of the depth of the air cushion, the pressure of the air cushion, and other air cushion characteristics. Water impact relief openings extend through the side hulls disperse wave impact energy through the side hulls. The center bow terminates forward of the flexible seal. However, flexible seals are subject to impact damage, fatigue, and wear. In rough seas, they dramatically add to the resistance and drag of the boat, thus slowing the boat down.
A vessel which utilizes a compressor to create an air cushion in a lower recess covered by a plurality of louvers arranged to vent pressurized air downwardly and rearwardly is revealed in Burgin U.S. Pat. No. 3,893,406 issued on Jul. 8, 1975. Burgin teaches a boat having a bottom, twin longitudinal depending keels adjacent the lateral edges of the bottom, extending the length of the bottom. Each keel includes a longitudinally extending passageway having an intake port at the bow end and an exhaust port adjacent at the stem end. An engine drives a respective water jet pump disposed in each passageway to draw water through the respective intake port and force the water out under pressure through the respective exhaust port. The engine drives a pair of rotary beaters at the respective intakes that keep trash out of the intake ports. The bottom of the boat is formed with a recess having a closed top, sides, and ends. An compressor driven by the engine delivers a flow of pressurized air into the recess. A plurality of louvers cover the recess, being arranged to vent the pressurized air downwardly and rearwardly to lubricate the hull moving through the water. A center bow reaches forwardly beyond the keels terminating at a forward end of the recess. The keels project downwardly and are lower than the forward seal and the level of air in the well. However, since the keel line of the boat extends downward with the keel being lower than the bow, the pressurized air in the air cavity escapes out of the front thereof being the highest point of the air cavity. The keels create significant drag.
A multi-hull xe2x80x9csurface effect shipxe2x80x9d (SES) vessel that combines with a xe2x80x9cwing in ground effect boatxe2x80x9d (WIG) is disclosed in Burg U.S. Pat. No. 5,611,294 issued on Mar. 18, 1997. Burg teaches a multi-hull gas cushion supported marine vessel that is capable of transition to airborne surface effect operation. The vessel has three elongate hulls having respective knife shaped bows that slice into waves. Each hull includes a lower recess having a very fine entry and low angle of side wall divergence containing a respective pressurized air cushion. The sidehulls include outer water rejecting steps that extend high onto the sidehulls, and retractable water stabilizers in the form of inverted-T hydrofoils for increased stability in heavy seas. Respective inverted-V shaped, gas cushion and wetdeck aft seals are provided to ensure minimum effect of wave impacts in those areas. The recesses are supplied with pressurized air by a respective powered blower with the recesses being sealable using a respective sealing flap. Each recess can be maintained at a positive pressure for maximum draft or at a negative pressure relative to ambient for a minimum above water profile such as for patrol boat applications where a minimum radar signature is desired. Connecting ducts with venturies interconnect the recesses to dampen pressure differences between the recesses and to supply pressurized air to a recess should the respective blower fail (the respective sealing flap being closed) to permit continued vessel operation until repairs can be made. The vessel can include a pair of retractable or fixed sidewings to add aerodynamic lift when the vessel is airborne. The sidewings may include outrigger hulls for added stability. However, the SES capabilities of this boat design will not lift any more than boat and crew, it will not carry a payload due to the limitations of SES designs. There is not enough square feet of air cushion, and far too much drag from the hulls and tunnels of the design in operation to even gain the benefits of WIG technology. The WIG technology has the same limitation as the SES of not being able to carry a payload. The combination of both is a highly technical design, expensive to build, expensive to operate, and expensive to maintain.
A vessel which utilizes blowers to create an air cushion in a pair of lower recesses is disclosed in Burg U.S. Pat. No. 5,000,107 issued on Mar. 19, 1991. This is a continuation in-part of U.S. Pat. No. 4,890,564 issued to Burg. The improvements over the previous design is the pressurized air cushions are restrained by modified recesses of the hull and by a plurality of movable forward seals such that some eighty to ninety percent of vessel weight is supported by the pressurized air cushions resulting in greater hull efficiency. The plurality of forward seals are placed in the pressurized air cushion so as to divide its functions. Differential air cushion portion pressures provide an improved ride for passengers. Zero or low angle to horizontal surfaces on sidehull forward lower and aft seal lower surfaces ensures good pressurized air sealing and better hull efficiency. The aft seal angled surfaces and forwardly extending bow also provide better ride qualities. The aft movable seal members are controllable to change the orientation of the hull using the pressurized air cushions. A narrower hull beam forward than aft which results in more attractive and easier riding bow sections. However, the boat is an improvement on the previous patent but has thee same inherent limitations.
A xe2x80x9cSurface Effect Shipxe2x80x9d (SES, twin hard sidewalls) cargo vessel with flat bottom planing pontoons (SEPPS) which utilizes a hovercraft type lift system and is claimed to be capable of operating at two to three times the speeds of conventional cargo vessels having the same horse power to weight ratios is disclosed in Bixel, Jr. U.S. Pat. No. 5,746,146 issued on May 5, 1998. Bixel, Jr. teaches a xe2x80x9czero draftxe2x80x9d cargo vessel with high speed open sea operational capabilities. The vessel is a catamaran type design which incorporates a hovercraft blower system capable of lifting the craft slightly out of the water with air escaping from the pressurized air cushion lubricating respective bottoms of the pontoon while planing for reduced water drag. A soft hovercraft air pad is contained within and stabilized by the pontoons. However, the boat is an SES design claiming to operate at the resistance of a hovercraft. A hovercraft is a highly inefficient vehicle. The design will never achieve the necessary speed and efficiency in operation as a loaded cargo vessel. The high speed planning surfaces will not offer enough flotation by themselves to float the boat as a shallow draft vessel. If they were big enough to float a cargo/load bearing vessel, the resulting drag in operation would be immense and the force of vertical impacts of the planning surface would crush the cargo. Additionally, the forward seal is so blunt that it will stop the boat in any seas beyond a light chop.
A race boat which utilizes aerated hydrochannels along the length of the boat to adjust the attitude of the hull is disclosed in Bronson U.S. Pat. No. 5,850,793 issued on Dec. 22, 1998. Bronson teaches a tri-hull vessel using air and water collectively channeled and controlled through its design to enhance speed and stability through the water. A pair of structural wings connect the outer hulls to the center hull and include respective flaps are adjustable to direct the flow of ambient air in the desired direction and into a pair of air intake. The which enters the air intakes passes through a respective air channel in each outer hull and exits into a respective hydrochannel formed in at the bottom of each outer hull. The exiting air on the water moving through each hydrochannel provides an upward force to the rear of each outboard hull resulting in a downward force to the bow of the tri-hull which enhances stability at high speeds. Adjustable air flow relief valves are provided for controlling the flow of air into hydro-channels and subfins beneath each outer hull provide traction during turns. However, the boat utilizes aerated hydrochannels which extend the length of the boat which are for stabilization and attitude control of the boat during racing. The hydrochannels raise the stem and lower the bow. This application is not for cargo vessels.
It is thus an object of the present invention to provide an integrated entry surface effect marine platform for powered and unpowered marine vessels and barges which has reduced drag through water.
It is another object of the present invention to provide an integrated entry surface effect marine platform which has superior wave penetration for rough sea operation.
It is a still further object of the present invention to provide an integrated entry surface effect marine platform of a monohull design.
It is still another object of the present invention to provide such an integrated entry surface effect marine platform which utilizes pressurized air to reduce friction with the water.
It is finally an object of the present invention to provide such an integrated entry surface effect marine platform which is supported in forward operation by a combination of floatation, pneumatic lift, and hydrodynamic lift
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
An integrated entry surface effect marine platform is provided including 1) a plurality of bows each including respective pairs of bow inclines that begin at an upper shear line and continue down and aft, respective outboard most of the bow inclines which extend aft and outboard to a transverse a stem seal forming respective outboard seals therealong; 2) a plurality of water flow channels, one channel being disposed between each pair of the plurality of bows; 3) a keel for each bow, the keels originating at respective bases of the bows and continuing aft and outboard from respective center lines of the bows; 4) a plurality of bow seals that originate at respective bases of the bows at respective forward ends of the keels and continue aft and outboard along respective of the keels until the keels blend into the water flow channels and the outboard seals; 5) an aft inclined lift surface that precedes the stem seal extending forward to an upper air cavity surface which extends into the respective water flow channels forming an air cavity thereunder, the air cavity originating at the bow seals, at the bases of the bows, at respective forward ends of the keels, the air cavity which continues aft and outboard along respective of the keels until blending into the water flow channels and the outboard seals; 6) at least one air discharge duct through top of the air cavity lift through which the pressurized air is delivered to the air cavity, and 7) wherein as the marine platform passes through the water, the aft inclined lift surface provides hydrodynamic lift to raise an aft end of the marine platform, the air cavity being filled with a flow of pressurized air from the air discharge ducts, the air cavity which restrains a cushion of pressurized air beneath the marine platform in operation to reduce water contact therewith to reduce laminar friction, the water flow channels which direct flows of displaced water from wave impacts into the air cavity wherein the air cushion and flow of pressurized air maintain the reduced contact with the water for reduced resistance and drag.